A turbocharger includes: an inflow passage to guide a fluid to a housing space for a turbine wheel; an exhaust passage to discharge the fluid having rotated the turbine wheel from a turbocharger body; a bypass passage connecting the inflow passage and the exhaust passage; a valve unit having one valve for a communicating portion between the exhaust passage and the housing space, and another valve for the bypass passage; an actuator to turn the valve unit and a stem connected to the valve unit about an axis of the stem; and a controller to operate the actuator. The controller adjusts the opening of the bypass passage by turning the valve unit within a specific range about the axis of the stem when a specific condition is met, and closes the exhaust passage by turning the valve unit beyond the specific range when the specific condition is not met.

In a method of reducing pollutants of a combustion engine, exhaust gas, generated by a cylinder of the combustion engine, is fed to an exhaust gas aftertreatment system as a function of a predefined condition solely via a first exhaust channel which communicates with a first one of first and second exhaust valves of the cylinder. The first exhaust channel is hereby coated, at least in part, by a thermally insulating layer selected such that a heat input is transmitted to the exhaust gas aftertreatment system which heat input is greater than a heat input in a second exhaust channel communicating with a second one of the first and second exhaust valves. The predefined condition is defined as a function of a coolant temperature of the combustion engine.

A supercharged internal combustion engine may include a twin-flow turbine with variable vane geometry. One example method to operate the device permits optimized operation of the internal combustion engine at low exhaust gas flow rates.

An internal combustion engine includes a cylinder block defining a cylinder and a cylinder head mounted to the block. The cylinder head supplies air and fuel to the cylinder for combustion therein. The engine also includes an exhaust manifold operatively connected to the cylinder head and having first and second outlets configured to exhaust post-combustion gasses from the cylinder. The engine also includes a turbocharging system including a low-flow turbocharger driven by the post-combustion gasses from the first outlet to pressurize the airflow and a high-flow turbocharger driven by the post-combustion gasses from the second outlet. The turbocharging system also includes a flow control device for selectively directing the post-combustion gasses to the low-flow and high-flow turbochargers. The turbocharging system additionally includes a motor-generator to selectively assist the post-combustion gasses in driving either the low-flow or the high-flow turbocharger and generate electric current when driven via the subject turbocharger.